This invention relates to positive displacement devices such as pumps and motors and especially to rotary-type devices as opposed to those that reciprocate (e.g., piston type). More particularly, the invention relates to such rotary devices wherein sealed cavities or chambers progress axially or in a direction generally parallel to an axis of rotation from an inlet to an outlet.
The several forms and variations of the invention may be adapted for use as a pump or motor for liquids and/or comminuted material, or as an expander or compressor for gases. The sealed cavities or chambers may be of constant volume during their axial progression as in the case of liquid pumps or motors or may have an expanding or diminishing volume as in the case of expanders or compressors for a gaseous medium. Alternatively, the device may be designed to first compress the chamber volume and then subsequently to expand it as in the case of an internal combustion engine.
The device of the invention constitutes an entirely new class of rotary motion devices, for use in connection with a liquid or gaseous medium and utilizes a revolutionary new mechanical concept that can be embodied in many and various applications.
While the device of the invention in its various forms utilizes three dimensional geometrical relationships with complex surface forms, one presently-known aspect of the unique geometry involved may be considered with respect to two-dimensional plane figures. This two-dimensional aspect is illustrated and described to a limited extent in U.S. Pat. No. 3,234,888 to Wise et al. and in U.S. Pat. No. 3,439,654 to Campbell.
More specifically, the two-dimensional expanding chamber device, as shown in the patent to Wise, has four elliptical impellers with symetrically spaced, parallel axes of rotation through their respective geometric centers to define along with the end walls of the device, a pumping cavity enclosed therebetween. The size of the cavity or chamber thus defined varies between minimum and maximum volumes depending on the relative orientation of the impellers throughout a rotary cycle. Also, suitable porting is provided for the fluid being pumped. The impellers are all driven through intermeshing gears to provide a synchronized rotation.
This same class of mechanical rotary motion devices is utilized in the internal combustion engine of the aforesaid Campbell patent wherein four cam pistons that rotate in synchronization are used to form an expanding and contracting combustion chamber. Here the rotary cam pistons are in the form of two-lobed, two-dimensional elements defined by two matching 90.degree. arcuate segments of a circle. Seals are provided at the tips of the cam pistons and a central post is located in the combustion chamber to cooperate with the seals and provide one intermittent condition wherein the chamber volume is essentially zero.
As indicated, these known mechanisms are essentially two-dimensional expanding chamber devices wherein porting is provided to transmit fluid to and from the chamber or cavity. The rotors alone do not define the enclosed volume but cooperate with end plates to define the expanding chamber.
The device of the present invention utilizes the two-dimensional geometric concept described above in that it adapts this concept to a three-dimensional axial flow concept wherein the chambers or cavities progress in an axial direction and are defined by the uniquely shaped surfaces of the interengaging rotors. Accordingly, the device of the present invention constitutes an entirely new concept in rotary motion mechanical devices and affords revolutionary new features heretofore not obtainable.